The Anopheles mosquito is most active at night and so prevention measures should be taken during this time.

Areas of Risk

In 2015, 91 countries had ongoing malaria transmission*. Malaria is widespread in many tropical and subtropical countries, particularly Sub-Saharan Africa which carries a disproportionately high share of the global malaria burden with 90% of global cases. However, South-East Asia, Latin America and the Middle East, are also at risk.

*http://www.who.int/mediacentre/factsheets/fs094/en/

Symptoms

Malaria is an acute feverish illness. Symptoms appear between 1 and 2 weeks after the infective mosquito bite. The first symptoms – fever, headache, chills and vomiting – may be mild and difficult to recognize as malaria. If not treated within 24 hours the most serious forms of the diease can progress in severity, and become life-threatening.

Treatment

Early diagnosis and treatment of malaria reduces disease and prevents deaths. If you suspect you have malaria you should seek emergency medical treatment as soon as possible and mention that you have travelled to a malaria zone as soon as possible. If you’re diagnosed with malaria, your doctor must tell the public health authorities. It’s important that anybody you travelled with is warned, so that they can look out for symptoms themselves.

Zika Virus

In 2015, an outbreak of the zika virus occurred in the Caribbean, Central and South America with some cases also reported in Oceania and parts of Asia.

Overview

The zika virus is primarily spread by mosquitoes, predominantly the Aedes mosquito. The Aedes mosquito is particularly active during the day. As there is still no available vaccination, bite prevention is the main form of protection from zika.

Areas of Risk

High risk areas include South and Central America and the Caribbean as well as parts of Florida in the USA and Thailand. Some counties in Africa, the Pacific Islands and Asia have reported zika in the past but the risk to travellers here is much lower than in countries with zika epidemics.

Symptoms

For most people zika symptoms involve a very mild infection which isn’t harmful. Symptoms can include fever, headache, muscle pain, joint pain, skin rash and conjunctivitis.

Treatment

There is no specific treatment for the zika virus. Treatment is primarily to relieve symptoms. Take paracetamol to reduce fever and pain and drink plenty of water. Do not take aspirin or ibuprofen as this can increase the risk of bleeding. If you are pregnant and suspect you have zika, contact a doctor immediately and inform him of your travel history.

Zika and Pregnancy

Zika virus can be passed from a pregnant woman to her foetus.

Infection during pregnancy can cause certain birth defects such as microcephaly. zika primarily spreads through infected mosquitoes but you can also get zika through sex. Pregnant women or couples planning a pregnancy are advised to postpone all non-essential travel to zika affected areas.

If travel is essential – mosquito bite prevention and contraceptive measures are advised.
If your partner has travelled to a zika affected area, protect yourself from sexual transmission by using a condom for at least 6 months after travel.

Couples should contact their doctor after visiting a zika affected area, even if you do not feel sick.

Dengue Fever

The global incidence of dengue has grown dramatically in recent decades.

Overview

As many as 400 million people a year are infected by dengue. It is caused by any one of four related viruses transmitted to humans by the Aedes mosquito. The Aedes mosquito is particularly active during the day in the early morning and late afternoon.

Areas of Risk

In many parts of the tropics and subtropics, dengue is endemic, in that it occurs every year, usually during a season when Aedes mosquito populations are high, often during rainy season.

Symptoms

About half of the worlds population is now at risk. Dengue fever is a severe, flu-like illness but seldom causes death. Dengue should be suspected when a high fever is accompanied by 2 of the following symptoms: severe headache, pain behind the eyes, muscle and joint pains, vomiting, swollen glands or rash. Symptoms usually appear 4-10 days after the infected bite.

Severe dengue is a potentially deadly complication, warning signs occur 3–7 days after the first symptoms in conjunction with a decrease in temperature (below 38°C/100°F) and include: cold clammy skin, severe abdominal pain, persistent vomiting, breathing difficulties, bleeding gums, and blood in vomit. The next 24–48 hours of the critical stage can be lethal; proper medical care is needed to avoid complications and risk of death.

Treatment

There is no specific treatment for dengue. Treatment is primarily to relieve symptoms. Take paracetamol to reduce fever and pain and drink plenty of water. Do not take aspirin or ibuprofen as this can increase the risk of bleeding.

Yellow Fever

Yellow fever is a serious viral infection, which is spread by the Aedes aegyptii mosquito and is endemic in Africa and South America.

Overview

Although a very rare disease, if infection occurs the risk of dying from yellow fever is significant.

Symptoms

Initial symptoms occur 3 to 6 days after exposure and include fever, nausea, vomiting, stomach-ache, headache and muscle pain. In severe cases jaundice occurs, which is the classic symptom of yellow fever, yellow skin and eyes.

Treatment

Seek professional medical advice prior to visiting a high-risk area. There is no treatment for yellow fever and this disease can only be prevented by immunisation and mosquito bite avoidance.

Travellers should alert their GP of any fever like illness occurring after leaving an endemic area.

West Nile Virus

West Nile virus can infect humans, birds, mosquitoes, horses and some other mammals, but is most common in birds.

Overview

Spread by the bite of an infected mosquito, in humans it generally produces only a mild illness. But, like many other arboviruses, it can produce serious infection of the brain, or encephalitis.

Areas of Risk

It is found in Africa, West Asia, Australasia, the Middle East and in North America*.

*http://www.who.int/mediacentre/factsheets/fs354/en/

Symptoms

The incubation period is between 3 to 14 days – however, 80% of those infected will not experience any symptoms and 20% will develop flu-like symptoms, including fever, headache and general aches and pains. Less than 1% of people infected with WNV will develop severe infection leading to encephalitis, which can be fatal. Severe infection is more likely in people over 50 and those with a weak immune system.

Treatment

Seek professional medical advice prior to visiting a high-risk area. The best protection against this virus is bite prevention.

Travellers should alert their GP of any fever like illness occurring after leaving an endemic area.

Chikungunya

Chikungunya is a viral disease transmitted to humans by the Aedes mosquito.

Overview

The Aedes mosquito is particularly active during the day in the early morning and late afternoon.

Areas of Risk

Chikungunya has been identified in over 60 countries in Asia, Africa, Europe and the Americas.

Symptoms

The symptoms of chikungunya can be severe and disabling and in rare cases, result in death. Chikungunya is characterised by an abrupt onset of fever frequently accompanied by joint pain. Other common signs and symptoms include muscle pain, headache, nausea, fatigue and rash. Most patients will feel better within a week but in rare cases joint pain may persist for months. People at risk from complications of chikungunya include newborns infected around the time of birth, older adults (≥65 years), and people with medical conditions such as high blood pressure, diabetes, or heart disease.

Treatment

There is no specific treatment for chikungunya. Treatment is primarily to relieve symptoms. Take paracetamol to reduce fever and pain and drink plenty of water. Do not take aspirin or ibuprofen until dengue can be ruled out to reduce the risk of bleeding.